Contraction-center-strip mold cap



June 10, 1930. v R. R. ROBERTSON 1,763,369

GONTRAFTION CENTER STRIP MOLD CAP lFiled June 20, 1929 Patented June 10, 1930 ROBERT n. ROBZER'rsOn, or CHICAGO, ILLINOIS ooNTnAoTroN-cnnrnnsmnri MOLD 'CAP Application ala June 2o,

In the construction of reinforced concrete roads `and the like it has `been found necessary to provide metallic center strips which are usually staked in position longitudinally t onthe center line of the road sub-grade and project upwardly with the upper edges of the center strips adapted to be positioned approximately One-half inch below the upper surface of the pavement after the concrete 1c has been poured to cover the sub-grade and to imbed the center strips. This method of construction requires a large amount of sheet metal'in the form of center strips which are ultimately left buried within the concrete forming the road.

To reduce the cost and amount ofsheet metal required in the form of center strips to be permanently left within a concrete road i andto furthermore provide a longitudinal with rounded edges formed on the concrete section on opposite sides of the center strips,

this invention has been devised to provide -T metallic `center strips of reduced height and thickness by providing removable improved mold caps having integral staggered clamping tongues or fiaps adapted to be frictionally engaged on the upper margin of the center strips with the tongues alternately engaging opposite surfaces ofthe center strips to hold the mold caps adj ustably mounted on the cen-` ter strips to position the bead heads of thef mold capsat a predetermined height above the top surface of the sub-grade so that after the concrete has been poured on the subgrade to enclose the center strips and the mold caps uniform rounded edges are providedon either `side of the expansion joint after the concrete has thoroughly set thereby permitting the mold caps to be removed from the road for reuse leaving the reduced center strips embedded in the road.

It is an object of this invention to provide an improved combination center strip and mold cap for concrete road construction affording an arrangement whereby the mold cap may be eventually removed when the concrete has thoroughly set leaving the center strip which is of reduced height and thickness,-in the concrete thereby materially reu er margin of the center stri to ro :erl 2@ center crack or groove 1n the concrete road pp a p p l y 1929. Serial No. 372,291.

ducing the amount of sheet metal required in providing a longitudinally disposed center groove with uniform rounded edges on either side of the expansion joint.

It is also an object of this invention to provide a `removable mold cap for forming a longitudinal crack in a concrete road, saidV mold cap being constructed of a depth sumcient to permit a center strip of reduced height and thickness to be used to materially A reduce the amount of metal which is required to permanently remain buried in the concrete road.`

It is a further object of this invention to provide a contraction center strip with a removable Vand an adjustable mold cap pro Vvided with resilient tongues adapted to be alternately engaged on opposite sides of the position rounded grooves formed in the mold cap bead to be positioned at a required height above the sub-grade of the road to adord a center groove or crack with uniformly rounded'edges when the mold cap is eventually removed from the concrete.

It is an important object of this invention to provide a combination center strip and mold cap with the center strip reduced in size and thickness while the mold cap which is eventually `removed from the road, constructedto an increased depth and provided with a `longitudinal upper bead having rounded grooves "on opposite sides thereof and furthermore having the lower portion of the mold cap provided with a plurality of resilient tongues or flaps adapted to be frictionally engaged in staggered relation on opposite sides of the upper margin of the center strip to permit vertical adjustment of the mold cap with respect to the center strip thereby affording an arrangement which permits removal and reuse of the mold cap and requires areduced amount of metal in the form of road strips to be permanently left within the concrete road. i

Other and further important objects of this invention will be apparent from the disclosures in the drawings and specification.

This invention (in a preferred form) is 190 soI illustrated in the drawingsV and hereinafter more fully described.

On the drawings:

Figure l is a fragmentary perspective view of a section of a concrete roadl having imbedded therein an improved combination center strip and mold cap embodyingthe principles of this invention.

Figure 2 is a fragmentary reduced sidetelevation of the combination center strip and l mold cap showing the mold cap in itsl'ower-` most position seated uponthe upper margin proved sheet metal center A-strip imbedded therein and resting upon the; top surface of the subgrade to afford a contraction joint forming device together with an improvedremovable mold `cap which is adjustablyfengaged-upon the upper margin of the center stri Y t he improved means for forming acontin yuous straight groove of substantiallyuniform widthA longitudinally valong the center or crown of the concrete road comprises a plurality of center strips mounted in longitudinal abutting alignment on the sub-grade with.

`each of said center strips comprising a plural- 'ity of flat metal flanges k3 disposed, in substantially the same plane and integrally connected by means of a longitudinally disposed intermediate trough or V cross sectioned-middle section 4. The improved center strip of this invention is adapted tobe constructed of light f weight metal and is of a height materially less than that usually employed vin concrete4 the road structure. n

road construction work. When inv position :.the center strip has the lower edge thereof seated upon the top surface of the concrete road sub-grade while the-up er longitudinal 'edge of the upper fian e 3.o theV center strip is positioned a consi erable distance below lthe eventual top surface or level of the crowned section of the concrete road.

The present invention has been devised as a Vmeans for materially reducing the amount of metal required to permanently remain irn- Ibedded in the crown sectionof a concrete road to reduce the cost of road construction workl by providing removable mold caps `which are adapted to be adjustably engaged on the upper flanges of vthe centerstrips to Vlill the 1vspace `between the upper edgeof the center strips and the top surface of the crown section of the road.

Each of the improved mold caps comprises a pair of adjacently positioned metal plates 5 and 6 which are spot welded together and have the upper edges thereof curved or rolled outwardly te formcurved beadstrips 7 which form a longitudinal bead or head `along the upper portion of the mold cap. Integrallyv formed on the vlower `marginal edge of the mold lcap side plate `5 are a plurality of tongues or Vfiaps Srgwhich are separated by notches or poc' 'ets 9; Integrally formed on -the lower margin ofthe mold cap plate 6 are a plurality of tongues or flps 10 separated by notches orfpocket's Yll. sclearlyiillustrated in Figures l and2 of the drawings the tongues or vflaps8 on-one side ofthe mold cap a-re'staggered` with respect to ythe tongues or flaps 10 formed on the .opposite side of the mold cap to afford an arrangement whereby the improved mold cap maybe adjustably engaged onthe'upper marginof the top flange .3 of the .center strip asillustratedin Figure -1. The tongues Sare adapted to be engaged' on one side `of the top flange vof the center strip while the tongues 10 are engaged adjacent the opposite sideof thetop flange ofthe center strip thereby resiliently and frictionally clamping i the mold cap adj ustably upon the upper edge or margin of the center strip. This arrangement permits the mold cap'to be first slightly 1 engaged ontthe center strip after which the y mold cap lmay be slightly tamped so that the Vsame will frictionally slide ldownwardly on the center strip a predetermined amount to properly Vposition Ythe bead or head of the mold cap at a predetermined elevationgabove y the top surfaceof the road subs-grade l. This provision of an adjustable 4and removable'.` mold cap for usein combination with a metal center strip permitsthe center :strip to be formed of thin sheet metal and of a reduced height so that thevamount of metal permanently remaining in the concrete road construction is materially reduced thereby, reducing thecost of construction without in any waysacriticing thequality or durability of With `a center strip and a mold cap supported in vertical position Aupon the lroad subgrade concrete is poured upon the-sub-grade `on opposite sides ofthe road strip until the upper level of the crown section is obtained. The concrete projects intothegroove afforded by the center strip intermediate channel section 4 and the'packs Yin the recesses provided by the rmold cap with the bead head of themold cap projecting slightly above the crown surface of the road. After they concrete has been permitted `to set a predetermined length o'ftime the mold cap is removed from the top of the center strip leaving a groovel of uniform width longitudinally along the center of the-crown of the road.

Figure 4 illustrates a modified form of mold l cap of a unitary construction comprising a pair of adjacently disposed plates 12 which are rigidlysecured together by brazmg or j other suitable means and are integrally conf nected at their upper margins by a head or bead 13.` The bead head 13 provides rounded grooves on opposite sides of the mold cap to permit uniformly rounded edges to be formed in the sections of concrete formed on opposite sides of the center strip and mold cap. Integrally formed in spaced relation on the lower longitudinal margin of each of the mold cap side plates 12 are a plurality of tongues or flaps 14 with the tongues or flaps 14 on one side of the mold cap staggered with respect to those on the opposite side. r1`he spaces provided between the tongues or flaps on each side of the mold cap are of sufficient length and are gauged according to the thickness of the metal of which the center strip is constructed.

Figure 5 illustrates another modilied form of mold cap which is also of unitary construction and embraces a single plate 15 the lower margin of which is notched to afford a plurality of spaced tongues or flaps 16. The upper margin of the mold cap plate 15 is bent around upon itself to form a bead or longi` tudinally disposed head 17 affording rounded" grooves on opposite sides of the bead for the j purpose of forming rounded uniform edges on the upper section of the concrete forming the crown portion of the road. 4 One margin of the bead or head 17 is directed downwardly to lie adjacent the plate 15 and is adapted to be rigidly secured thereto by brazing or other suitable means. In this form of the device the mold cap is only provided with one row of tongues or flaps 16 spaced a sufficient distance apart to permit the tongues to be engaged on the upper margin of the center strip with said tongues alternately disposed on opposite sides of the top flange of the center strip as is clearly illustrated in Figure 5. With the arrangement shown the mold cap may be set in position with the tongues only slightly engaging the upper flange of the center strip to permit the mold cap to be tampered to move the same downward required distances depending upon the level at which it is desired to position the top bead head 17 of the mold cap. i

Attention is called to the fact that in providing removable and adjustable mold caps of the improved type. hereinbefore described said mold capsmay be made of sheet metal so formed that the plates `forming part of the mold cap may be of any desired depth so that the tongues or flaps when in position may be engaged on the upper flanges of the center' strip. l/Vith this arrangement it will be noted thatthe center stripmay be of reduced thickness and height thereby materially reduc'- ing the amount of metal required in the construction of aroad for the purpose of providing a `definite weakness in the pavement allowing the concrete to crack in a straight continuous plane or line. After the forming of the centen crack or groove the same is adapted to be filled with a bituminous substance to provide a permanent marked line throughthe center of the pavement. The improved mold cap being constructed to permit removal of the same permits the mold cap to be repeatedly reused on center strips which may be of reduced size and which are permanently left in the concrete road structure.

1t will of course be understood that various details of construction may be varied through a wide range without departing from the principles of this invention, and it is therefore not purposed limiting the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A contraction center strip mold ca comprising a body portion, a bead heald formed thereon and providing rounded grooves on opposite sides of the mold cap,

and a plurality of tongues formed on the body portion adapted to be engaged on a center strip with the tongues engaged in staggered relation on oppositesides of said center strip.

2. A contraction center strip mold cap comprising a body portion, a bead head integrally formed on the upper longitudinal margin thereof to provide rounded grooves, and a plurality of spaced tongues integrally formed on the lower longitudinal margin of said body portion.

3. A. contraction center strip mold cap comprising a body portion, a bead integrally formed thereon having rounded outwardly deflected portions to provide uniform rounded edges on either side of a concrete joint, and extensions integrally formed on the body portion and spaced from one another a distance sufficient to permit the extension to be removably engaged in staggered relation upon the upper margin of a contraction center strip.

4. A contraction center strip mold cap comprising a plate, spaced projections integrally formed on one longitudinal margin thereof and a deflected bead member integrally formed on the other longitudinal margin thereof.

5. rlhe combination with a contraction center strip, of a mold cap removably engaged thereon having a top bead .projecting on opposite sides thereof-and also havinga plurality of spaced. ltongues `integrally formed thereon `adapted to fbe engaged in staggered relation on opposite sides of .the upper margin of the center strip.

6. The combination with ya contraction center strip, of a mold vcap having rounded grooves on opposite sidesv thereof, and resilif ent members integrally formed onfthe mold cap adapted to be frictionally engaged on the center strip to permit the mold cap to beadjusted with respect to the center strip. i

In testimony whereof I have hereuntosub- 15 scribed my name at Chicago, Cook CountyE Illinois. Y e y,

ROBERT R. ROBERTSON. 

